Roger Rabbit, Don Quijote, Darts and how to avoid the fate of dinosaurs

Adam Plouff, Acme Falling Piano

Imagine you are Roger Rabbit playing a dangerous game of chance, choosing between two unopened doors. Behind door number one you get a 500-kilogram grand piano being dropped on your head from a height of one kilometer. Behind door number two you get 500 kilograms of foam balls dropped on you from the same height. Which do you choose? If you are Roger you might choose door number one, but a Scientific American reader would choose door number two. Why?

If you are a Mind The Post reader you do not need any further explanation… Anyway, you can continue reading here.

Philip Lubin and Alexander Cohen explain their proposal for a new planetary defense method, which they call PI (yes, like π), which is short for “Pulverize It!”. Their idea is to effectively pulverize any threatening asteroid into a large number of smaller fragments circa 10 meters or less in diameter. They think it is possible because asteroids have low surface gravity and most are easy to breakup and disperse.

We present a practical and effective method of planetary defense that allows for extremely short mitigation time scales. The method involves an array of small hypervelocity kinetic penetrators that pulverize and disassemble an asteroid or small comet. This effectively mitigates the threat using the Earth’s atmosphere to dissipate the energy in the fragment cloud. The proposed system allows a planetary defense solution using existing technologies. This approach will work in extended time scale interdiction modes where there is a large warning time, as well as in short interdiction time scenarios with intercepts of minutes to days before impact.

Lubin, P. (2021). PI — Terminal Planetary Defense. ArXiv:2110.07559 [Astro-Ph, Physics:Physics].

Lubin’s proposal departs from the mainstream proposal—deflecting potential threats so they will not hit us.

The Double Asteroid Redirection Test (DART) is a planetary defense-driven test of technologies for preventing an impact of Earth by a hazardous asteroid. DART will be the first demonstration of the kinetic impactor technique to change the motion of an asteroid in space. DART will launch aboard a SpaceX Falcon 9 rocket from Vandenberg Air Force Base, California. The spacecraft launch window begins November 24, 2021.

Two different views of the DART spacecraft. NASA

The target for the DART demonstration is Didymos, a sub-kilometre asteroid and synchronous binary system, classified as potentially hazardous asteroid and near-Earth object discovered in 1996. After separation from the launch vehicle and over a year of cruise it will intercept Didymos’ moonlet in late September 2022, when the Didymos system is within 11 million kilometres of Earth. The DART spacecraft will achieve the kinetic impact deflection by deliberately crashing itself into the moonlet at a speed of approximately 6.6 km/s, with the aid of an onboard camera (named DRACO) and sophisticated autonomous navigation software.

Didymos is but a drop in the sea of asteroids lurking around.

Known Near-Earth objects – as of January 2018, NASA
Map of recent 873 events greater than 0.073 Kt from April 15, 1988 to Sept 29, 2021 air burst impacts from atmospheric infrasonic sensors. Figure 2 in Lubin’s paper.

While the chances of a major collision are low in the near term, it is a near-certainty that one will happen eventually unless defensive measures are taken. In other words, It’s not a matter of “if” but “when”. Not surprisingly Lubin is sceptical about the actual capability to anticipate and actuate in time.

In June 2018, the US National Science and Technology Council warned that America is unprepared for an asteroid impact event, and developed and released the “National Near-Earth Object Preparedness Strategy Action Plan” to better prepare.

Don Quijote, for example, is a past space probe concept, similar to DART, by the European Space Agency to investigate the effects of crashing a spacecraft into an asteroid to deflect an asteroid on a collision course with Earth. The mission did not proceed beyond initial studies. Currently ESA is working on Asteroid Impact and Deflection Assessment mission as a part of its NEO space mission studies.

The recent pandemic shows us clearly that, even when the scientific community is well aware of potential (even existential) threats, society is too concentrated on our terrible day to day “existing” problems. Everything which is not scheduled in your boss’ agenda or your own is then, when it happens, a black swan

Just as if we were dinosaurs!

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